"This is a very difficult letter to write. I hope you will not hate us too much.... My son broke into your home recently while you were out." In a quiet, leafy suburb in upstate New York, a teenager has been sneaking into houses - and into the owners' computers as well - learning their secrets, and maybe sharing some of them, too. Who is he, and what might he have uncovered? After two anonymous letters are received, whispers start to circulate, and suspicion mounts. And when a woman down the street is found murdered, the tension reaches the breaking point.

Ten years ago he killed my son. Today I married him. Ten years ago my darling son Jesse was murdered and our perfect family was destroyed. My strong, handsome boy, so full of life, became a memory, a photo I carried with me everywhere. But today I’m finally close to finding happiness again. My ash-blonde hair has been curled into ringlets. Carefully placed white flowers frame my delicate features. The small, drab chapel has been prettied up with white satin, and there are tiny red hearts scattered on the small table where I will soon sign the register with my new husband. 

January 1992. A baby girl is left alone for a moment. Long enough for a mother to dash into a shop. Long enough for a child to be taken. Thirteen years later, solicitor Robert Knight's stepdaughter wins a place at a prestigious London school for the gifted. The only puzzle is his wife Erin's reaction. Why is she so reluctant to let Ruby go? Doesn't she want what's best for her? As Erin grows more evasive, Robert can't help but feel she has something to hide and when he stumbles on mysterious letters, he discovers she has been lying to him. 

Ava only left her daughter in the pushchair for five minutes. The buckle was fastened, and she was sure it was safe. But when she came downstairs, the door was open and Abi was gone - she walked down the road, past the Lovegoods' house, and was never seen again. A year later, the Lovegoods throw a housewarming party, showing off the results of their renovation. Ava doesn’t want to go. She can’t bear to look down that end of the road, to see the place where Abi vanished, and she doesn’t want to spend time with people who don’t share her grief. 

Pete Riley answers the door one morning and lets in a parent's worst nightmare. On his doorstep is Miles Lambert, a stranger who breaks the devastating news that Pete's son, Theo, isn't actually his son - he is the Lamberts', switched at birth by an understaffed hospital while their real son was sent home with Miles and his wife, Lucy. For Pete, his partner Maddie, and the little boy they've been raising for the past two years, life will never be the same again.

When I arrive unannounced at my husband's studio in need of a shoulder to cry on after hearing that my best student, Alex, has died, I see a pair of wineglasses drying by the sink, and my deepest fear is confirmed: my husband is having an affair. Most women would fall to their knees in tears and throw him out of the house - but I just can't bring myself to do it. Instead, I go home and cook a healthy dinner for our children, walk the dog, and unload the dishwasher without complaint. I need this marriage to work to protect a terrible secret of my own....

Owen Pick’s life is falling apart. In his 30s and living in his aunt’s spare bedroom, he has just been suspended from his job as a teacher after accusations of sexual misconduct - accusations he strongly denies. Searching for professional advice online, he is inadvertently sucked into the dark world of incel forums, where he meets a charismatic and mysterious figure. Across the street from Owen lives the Fours family, headed by mom Cate, a physiotherapist, and dad Roan, a child psychologist. But the Fours family have a bad feeling about their neighbor Owen.

When she was 9 years old, Melody Browne's house burned down, and it took all of her childhood memories with it. Now she's a single mother of a teenage boy living in Central London. She hasn't seen her parents since she left home at 15, but she doesn't mind. She's better off on her own. She works as a dinner lady at her son's school and has no idea where her humdrum life is heading. But one summer's night, a hypnotist inadvertently unlocks memories of her childhood, and her whole life is turned upside down.

For 15 years, Lexi and Jake have played the same six numbers with their friends. Over drinks, dinner parties, and summer barbecues, the three couples have discussed the important stuff - kids, marriages, careers - and they’ve laughed off their disappointment when they failed to win anything. But then, the unthinkable happens. There’s a rift in the group. Someone is caught in a lie. And soon after, six numbers come up that change everything forever.

It was supposed to be the happiest day of her life. Zoe was sitting in her hotel room, in her perfect white dress, looking forward to the moment when she would make kind, handsome Toby her husband. Then, there was a blank. They said she must have fainted, overcome with emotion. But nothing felt quite right afterward. Did something happen in that missing time? 

Selena Murphy is commuting home on the train when she strikes up a conversation with a beautiful stranger in the next seat. The woman introduces herself as Martha and soon confesses that she’s been stuck in an affair with her boss. Selena, in turn, confesses that she suspects her husband is sleeping with the nanny. When the train arrives at Selena’s station, the two women part ways, presumably never to meet again.

You're home making dinner for your husband. You expect him any second. The phone rings - it's the call you hoped you'd never get. You jump in your car and race to a neighborhood you thought you'd never visit. You peer into the dark, deserted building. You brace yourself for the worst. And then, you remember nothing else. They tell your husband you've been in an accident. You lost control of your car as you sped through the worst side of town. The police suspect you were up to no good. But your husband refuses to believe it.

Hannah has done everything to make sure her life is safe and secure. A long way from her unstable childhood growing up in foster care, she’s content with her sweet, little, messy apartment and her satisfying job as a social worker. She quietly worries that, aged 36, she might never fall in love. But otherwise her life is where she wants it to be. Until, encouraged by her best friend to join a dating app, she meets Alex. He’s irresistibly handsome. He loves the same music as her. The same food as well. 

It's winter in the Catskills and Mitchell's Inn, nestled deep in the woods, is the perfect setting for a relaxing - maybe even romantic - weekend away. So when the weather takes a turn for the worse, and a blizzard cuts off the electricity - and all contact with the outside world - the guests settle in and try to make the best of it. Soon, though, one of the guests turns up dead - it looks like an accident. But when a second guest dies, they start to panic. Within the snowed-in paradise, something - or someone - is picking off the guests one by one.

Gen is on the verge of a divorce from her cheating husband. When her sister, Meg, has a convention to attend in the Big Apple, she invites Gen along to celebrate her newly found freedom. But the perfect sisters’ getaway quickly goes awry when a tipsy Gen defiantly throws her wedding ring off the hotel room’s balcony. Then, wanting some fresh air, she decides to take a late-evening walk alone and vanishes without a trace.